Many pharmaceutical active ingredients, in addition to having excellent activity in their appropriate application, also have abuse potential, i.e. they can be used by an abuser to bring about effects other than those intended.
Opioids, for example, which are highly active in combating severe to very severe pain, are frequently used by abusers to induce a state of narcosis or euphoria.
In order to make abuse possible, the corresponding dosage forms, such as tablets or capsules are comminuted, for example ground in a mortar, by the abuser, the active ingredient is extracted from the resultant powder using a preferably aqueous liquid and the resultant solution, optionally after being filtered through cotton wool or cellulose wadding, is administered parenterally, in particular intravenously. An additional phenomenon of this kind of administration, in comparison with oral abuse, is a further accelerated increase in active ingredient levels giving the abuser the desired effect, namely the “kick” or “rush”. This kick is also obtained if the powdered dosage form is administered abusively nasally, i.e. is sniffed. Since delayed-release dosage forms containing active ingredients with potential for abuse do not give rise to the kick desired by the abuser when taken orally even in abusively high quantities, such dosage forms are also comminuted and extracted in order to be abused.
U.S. Pat. No. 4,070,494 proposed adding a swellable agent to the dosage form in order to prevent abuse. When water is added to extract the active ingredient, this agent swells and ensures that the filtrate separated from the gel contains only a small quantity of active ingredient.
The multilayer tablet disclosed in WO 95/20947 is based on a similar approach to preventing parenteral abuse, said tablet containing the active ingredient with abuse potential and at least one gel former, each in different layers.
WO 03/015531 A2 discloses another approach to preventing parenteral abuse. A dosage form containing an analgesic opioid and a dye as an aversive agent is described therein. The colour released by tampering with the dosage form is intended to discourage the abuser from using the dosage form which has been tampered with.
Another known option for complicating abuse involves adding antagonists to the active ingredients to the dosage form, for example naloxone or naltexone for opioids, or compounds which cause a physiological defense response, such as for example ipecacuanha (ipecac) root.
Since, however, as in the past, it is in most cases necessary for the purposes of abuse to pulverise the dosage form, it was the object of the present invention to provide a process for the production of dosage forms containing active ingredients with potential for abuse, which, when correctly administered, ensure the desired therapeutic action, but from which the active ingredients cannot be converted into a form suitable for abuse simply by pulverisation.